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Abstract

Background

An estimated 0.5 to 1.5 million informal miners, of whom 30-50% are women, rely on
artisanal mining for their livelihood in Tanzania. Mercury, used in the processing
gold ore, and arsenic, which is a constituent of some ores, are common occupational
exposures that frequently result in widespread environmental contamination. Frequently,
the mining activities are conducted haphazardly without regard for environmental,
occupational, or community exposure. The primary objective of this study was to assess
community risk knowledge and perception of potential mercury and arsenic toxicity
and/or exposure from artisanal gold mining in Rwamagasa in northwestern Tanzania.

Methods

A cross-sectional survey of respondents in five sub-villages in the Rwamagasa Village
located in Geita District in northwestern Tanzania near Lake Victoria was conducted.
This area has a history of artisanal gold mining and many of the population continue
to work as miners. Using a clustered random selection approach for recruitment, a
total of 160 individuals over 18 years of age completed a structured interview.

Results

The interviews revealed wide variations in knowledge and risk perceptions concerning
mercury and arsenic exposure, with 40.6% (n=65) and 89.4% (n=143) not aware of the
health effects of mercury and arsenic exposure respectively. Males were significantly
more knowledgeable (n=59, 36.9%) than females (n=36, 22.5%) with regard to mercury
(x2=3.99, p<0.05). An individual’s occupation category was associated with level of knowledge
(x2=22.82, p=<0.001). Individuals involved in mining (n=63, 73.2%) were more knowledgeable
about the negative health effects of mercury than individuals in other occupations.
Of the few individuals (n=17, 10.6%) who knew about arsenic toxicity, the majority
(n=10, 58.8%) were miners.

Conclusions

The knowledge of individuals living in Rwamagasa, Tanzania, an area with a history
of artisanal gold mining, varied widely with regard to the health hazards of mercury
and arsenic. In these communities there was limited awareness of the threats to health
associated with exposure to mercury and arsenic. This lack of knowledge, combined
with minimal environmental monitoring and controlled waste management practices, highlights
the need for health education, surveillance, and policy changes.

Keywords:

Background

Artisanal mining is increasingly common in many parts of the world with more than
30 million active artisanal miners in more than 55 countries [1,2]. In Tanzania alone, there are an estimated 0.5 to 1.5 million informal miners, of
whom 30-50% are women [1]. In fact, the number of artisanal mining sites is expanding in many regions of Tanzania,
particularly around Lake Victoria and in the central and southwestern regions of the
country. Artisanal mining activities are largely concentrated in rural areas that
have very little infrastructure, and the individuals undertaking informal mining generally
lack education, training, management skills and essential equipment for safe mining
practices.

Mercury (Hg), used in the processing of gold ore, and arsenic (As), which is a constituent
of some gold ores, are common occupational exposures that can result in widespread
environmental contamination. Frequently, the mining activities in Tanzania are conducted
haphazardly without consideration of environmental, occupational or community exposures.
Further, environmental monitoring and waste management in artisanal gold mining areas
in Tanzania is minimal.

Hg and As are known toxicants that are hazardous to humans, wildlife and domestic
animals and may accumulate in the environment causing serious damage to ecosystems
and human health [3,4]. Studies conducted throughout the world, including Tanzania, where artisanal mining
occurs have reported the presence of high Hg concentrations in human urine, breast
milk, blood, hair, and nails, and in plant and fish samples [5-13]. These studies have noted that Hg exposure due amalgamation and inhalation has escalated
since 1972. High levels of Hg and As have been linked to detrimental effects on humans,
such as skin problems, cancer, high blood pressure, cardiovascular diseases, and neurological
and reproductive disorders among others [7,11]. However, the burden of disease from Hg and/or As exposure in Tanzania has not been
widely examined. Other studies in Geita (Tanzania) have revealed that most of the
children living in Hg-exposed areas and those working with Hg display neuropsychological
deficits, which are associated with Hg exposure [5,8].

Most of the people living in close proximity to artisanal mining areas are vulnerable
to Hg and As exposure. The potential harm of these toxicants to pregnant women, their
fetuses and young children is an area of special concern. Women in these gold mining
regions may engage in geophagy, or earth-eating, behaviors, which are common in artisanal
mining areas due to poor nutritional status and cultural acceptance of this practice
[14]. Modest consumption of 50 g of sikor (i.e., a moulded soil sold in the local market)
from an As contaminated area per day is said to be equivalent to intake of 370 μg
of As [15]; however, this depends on the degree of contamination of the soil used to make the
sikor [14]. More alarming is the fact that low Hg exposure in mothers due to this practice could
result in the fetus being exposed to high levels of Hg as it is concentrated by a
factor of ten in the fetus relative to the mother [16]. Thus, even a woman with a low level of mercury exposure could give birth to a child
with significant birth defects. In addition, Hg exposure due to transmission through
breast milk could have an effect on the healthy development of infants [8]. Finally, infants and children are sometimes directly exposed to the mining processes
themselves, since mothers often have their children at the mine site and processing
areas while they are working and sometime young children even participate in mining
as workers.

Symptoms of Hg and As exposure are characterized by peripheral neuropathy and acrodynia
among others [17-20], which can result in social stigmatization among the affected individuals. Women
suffer the most in this regard, and may have difficulty finding a husband as they
are regarded less attractive, unhealthy and possibly as having sexual problems [21].

How a person perceives the symptoms of Hg and As poisoning and the associated morbidities
and mortalities − risk perception − can affect how one acts and the decisions one
makes concerning avoidance, control or protection against exposure [22]. In Tanzania, the knowledge and perception of people who live in close proximity
to artisanal mining with regard to the potential health risks of exposure to Hg and
As is unknown. Hg and As exposure add to the environmental burden of disease in Tanzania
and could be minimizing achievement of the Millennium Development Goals for reducing
child mortality, improving maternal health and ensuring environmental sustainability
(i.e., MDGs 4, 5 and 7, respectively) [23]. The primary objective of this study was to assess community risk knowledge and perception
of potential Hg and As toxicity and/or exposure from artisanal gold mining in Rwamagasa
Village in Geita District in northwestern Tanzania.

Methods

The study was conducted at the village of Rwamagasa located in Geita District (7,825 km2) (Figure 1). Geita first came into prominence as the site of a German colonial gold mine in
1900s. Artisanal miners have been working in the area since 1972, and currently there
are more than 300 active miners. The estimated total population of Rwamagasa is 7768
(3764 males and 4004 females), according to village records. Most people in the village
depend on water from rivers, natural wells, and wells constructed for human and livestock
consumption and for mining. Only 12% of the population has access to a protected public
well [5,24,25].

Using a cross sectional design with a clustered random sampling technique, 159 people
were targeted for recruitment into the study and 160 individuals consented and participated
in the face-to-face structured interview. All of the individuals approached agreed
to participate, (response rate was 100%). These participants were from five sub-villages
(clusters), CCM (n=54), Elimu (Isenyi) (n=28), Imalanguzo (n=25), Isingilo (n=27)
and Nyakayenze (n=26) with populations of 4641, 884, 603, 538, and 362 respectively.
Since mining is not physically segregated from the community, but rather occurs in
close proximity to housing and other economic activities, all people over the age
of 18 were considered eligible to participate.

Knowledge and perception data were collected using a structured interview, which was
pre-tested and amended prior to conducting fieldwork. Research assistants were recruited
and were trained regarding the study’s purpose and methods to ensure consistency and
reliability of data collection. In addition, the principal researcher (EC) supervised
all associated activities. The survey instrument was initially designed in English,
translated to Kiswahili, and then translated back to English by another translator
to ensure that the translated version captured the questions correctly. The interviews
were conducted in Kiswahili, which was the primary language of the interviewers and
interviewees. All field data were recorded on field data sheets/checklists, and were
double-entered to ensure accuracy.

The survey consisted of four sections: 1) demographics, 2) potential risk for Hg and
As exposure from animal, food, and water sources, 3) knowledge and risk perception
of Hg and As, and 4) mining practices, particularly with regard to environmental considerations
related to Hg. The survey included categorical questions (“Yes”, “No”, “Don’t know”
and “Not Applicable”), questions that required the participant to rate their response
on a Likert scale (“very low”, “low”, “normal”, “high”, “very high”) to determine
their level of agreement with a statement, and open-ended questions. Participant’s
knowledge of Hg and As poisoning was determined from basic questions regarding their
awareness of associated health impacts. Six questions were scored “1” for a correct
answer and “0” for incorrect answer. Respondents were classified as knowledgeable
if they obtained total scores of ≥ 2 and not knowledgeable if they obtained a total
score of < 2. With respect to perceptions about the cause of the morbidities and mortalities
associated with Hg and As toxicity, a similar scoring scheme was applied to questions
that asked about: 1) the cause of morbidities such as skin pigmentation problems,
hyperpigmentation, edema, excessive perspiration, brain damage and cancer; 2) participants
agreement with the statement that Hg and As environmental contamination might be a
cause of brain damage, edema, cancer, and skin pigmentation problems among individuals
living in the area; and 3) whether the cause of death of a participant’s parent was
associated with Hg and/or AS related symptoms. A respondent whose answer to any one
of the questions indicated that they perceived Hg or As as the cause for specific
health-related morbidities/mortalities was given a score of “1”. Participants who
obtained a score of “1” were classified as having a clear perception; individuals
with a score of less than “1” were classified as having a negative perception of Hg
and As morbidities and mortalities. All questions were considered to have equal weight.

Ethical approval was obtained from the Directorate of Postgraduate Studies of the
Weill Bugando University College of Health and Allied Sciences, and permission to
conduct the research in Mwanza Region and Geita District was obtained from the offices
of the Regional and District Commissioners. Written informed consent was obtained
from each participant. Importantly and contributing to the successful response rate,
the investigators obtained the support of the miners and the community for the study
by visiting and introducing the purpose and importance of the study to the entire
community at Rwamagasa. The investigators also provided the miners with personal protective
gear, such as dust masks and latex gloves.

Data were analyzed using Statistical Package for the Social Sciences (Version SPSS-17.0)
after checking and cleaning for discrepancies. Chi-square tests (Fischer’s Exact Test)
were used where appropriate to determine the association between socio-demographic
variables (which included sex, age, education level, marital status, economic activities
and how long the person had lived in the study area) and the outcomes of interest
(knowledge of potential health risks of Hg and As and associated factors were categorized
into two groups: knowledgeable and not knowledgeable). The association was considered
statistically significant when p-values were less than 0.05, Odd Ratios (OR) were
used as a measure of association and reported with 95% confidence intervals.

Results

The age of the participants ranged from 18 years to 71 years; however, most were between
25 and 38 years of age (n = 91, 56.9%). Forty-eight (30%) had lived in Rwamagasa for
one to five years, and twenty-eight (17.5%) had lived in the area for six to ten years.
Only fourteen of the respondents (n =14, 8.8%) had lived in Rwamagasa for more than
30 years. The CCM sub-village was the main center for mining activities and had the
largest population. Among the study population, the proportion of participants who
had not received any primary school education (referred to as illiterate) was 15.6%
(n = 25) for males and 19.4% (n = 31) for females. Economic activity was defined as
the major activity that the participants engaged in as the source for their secure
livelihood. The majority of the sample at Rwamagasa were miners (n=86, 53.8%), followed
by farmers (n=63, 39.4%). A few of the participants work in public services and retail
businesses (n=11, 6.9%).

The level of knowledge about the environmental and health risks of Hg and As toxicity
among individuals at Rwamagasa is summarized in Table 1. Of those surveyed, 65 individuals (40.6%) were not aware of Hg toxicity and 143
(89.4%) were not aware of As toxicity. Most of the participants (78.8%, n=126) were
unable to identify any specific symptoms associated with Hg exposure. Only 21.3% (n=34)
were able to identify at least one symptom. The majority of the participants (66.3%,
n=106) stated there were no health effects. In comparison, when the participants were
asked about malaria, most of the respondents mentioned more than one symptom, such
as headache (n=36, 22.5%), body weakness (n=35, 21.9%), fever (n=29, 18.1%), profuse
sweating (n=39, 21.3%) and loss of appetite (n=26, 16.3%).

Table 1.Knowledge about Mercury and Arsenic toxicity among individuals in Rwamagasa area

Sex and the economic activity of an individual were found to be significantly associated
with knowledge regarding Hg toxicity; sex (x2=3.99, p=0.046) and economic activity (x2=22.82, p<0.001). Males were significantly more knowledgeable (n=59, 36.9%) than females
(n=36, 22.5%). Most of the participants (n=143, 89.4%) had no knowledge about As toxicity;
however, significant associations were found between knowledge of As toxicity and
economic activity (x2=17.83, p<0.001) and education level (x2=10.79, p=0.005). This indicates that, of the few individuals (n=17, 10.6%) who knew
about As toxicity, most were miners (n=10, 58.8%) and most (n=16, 94.1%) had primary
education and above.

There was significant variability among respondents in terms of their perceptions
regarding the cause of the morbidities and mortalities associated with Hg and As toxicity.
Some of the respondents associated morbidities related to Hg and As exposure with
an evil spirit or witchcraft (n=33, 20.6%), others associated them with god’s curse
(n=17, 10.6%), and still others indicated that they were caused by contagious diseases,
such as HIV/AIDS (n = 64, 40%). Only 46 individuals (28.8%) associated the Hg and
As morbidities and mortalities with Hg and As toxicity (Table 2).

Table 2.Perception on mercury and arsenic toxicity and related morbidities and mortalities

Discussion

In Rwamagasa, along with the high proportion of people earning their livelihood from
mining, the low literacy levels of the random sample of individuals who participated
in this study suggest that risk reduction through education, training, behavioral
modifications, land use decisions, and health care delivery could be challenging.
However, a lesson on improving the livelihood of artisanal miners can be taken from
Sadiola in western Mali, where a successful diversification of artisanal miners was
achieved in 1997 by introducing alternative means for securing livelihood [26]. Fundamentally, the environmental health of the community must be addressed without
jeopardizing the rights of individuals to secure a livelihood.

Even with the increase in artisanal mining activities in Tanzania, community-based
and/or occupational health education programs that focus on the health hazards of
Hg and/or As exposure are severely lacking. In Tanzania, the amount of money and effort
spent on the risks education of miners is considerably lower than that spent on enforcement
and monitoring [27,28]. In Rwamagasa for instance, there was only one poster advocating the use of cleaner
technology located at the ward executive’s office. This likely had little effect because
of the low level of literacy of the individuals who visit the office. Health promotion
campaigns on the recognition of the symptoms and signs of Hg and As poisoning should
be established in rural communities with artisanal mining, including Rwamagasa. Further,
local health facilities should be equipped and health workers trained to conduct heavy
metal testing [29].

Even with knowledge and awareness, there is often no relationship between how one
acts and the decisions one makes concerning avoidance, control or protection against
exposure [22,28]. So, while the findings of this study indicated that the majority of the miners had
some basic knowledge about Hg toxicity and associated morbidities, it has been reported
that artisanal miners continued to use Hg with their bare hands and to burn the amalgam
in open air [24,27]. The necessity of generating a livelihood often outweighs the potential negative
health outcomes.

Women and children carry a particular burden with regard to toxic exposures. Even
though women are usually the primary caregivers to children, they are less likely
to know about the health effects associated with Hg exposure compared to men and so
are disadvantaged in making decisions about exposure reduction. Additionally, at every
mining location visited by the researchers, women miners were observed with their
infants and young children. Children were also often directly involved in working
directly in the mining activities. Thus, not only is the mother directly exposed to
Hg, but so are her children.

Among the respondents, almost half reported knowing about abnormalities, including
birth defects and skin discoloration, among infants in the study area. Although not
all birth defects are caused by toxic chemicals, birth defects are more common in
areas where industries, such as artisanal gold mining use or produce toxic chemicals
or wastes such as Hg [30]. Further research is needed that examines the relationships among Hg and As exposure
and congenital anomalies in this population.

Some signs of Hg poisoning are easy to confuse with malaria [17,30,31], which has implications for awareness and subsequent prevention and treatment. The
following symptoms are associated with both malaria and Hg poisoning: peripheral neuropathy,
itching, hypotonia (muscle weakness), tachycardia, nausea and sometimes vomiting,
visual problems, profuse sweating, headache, respiratory tract infections, fever,
rigors, tiredness, myalgia (limbs and back), abdominal pain, loss of appetite, hypertension
(especially for Hg poisoning) and postural hypotension (especially in malaria), enlarged
liver and spleen, coma and eventually death [17,31]. Malaria is a common chronic health problem in this region [32], and so people generally have a relatively high degree of awareness and familiarity
with it. In addition to the questions about Hg, respondents were also asked about
malaria symptoms; perhaps not surprisingly, most participants were able to correctly
identify at least one symptom of malaria, but were not able to do the same for Hg
poisoning. There is a need for further investigation on the co-morbidities of chronic
Hg exposure with malaria in artisanal mining areas.

Partnership is absolutely essential in addressing the elements of environmental health
and in reducing the health risks due to artisanal mining, as noted in the Ottawa Charter
for Health Promotions [22]. Governments, donors, NGOs and other stakeholders should emphasize the necessity
of recognizing the importance of artisanal mining and focus on creating supportive
environments for building social-economic capital, including legal, financial, technical,
cultural, and political issues [27]. This could provide individuals and groups with access to resources and support that
reduce the health risks to those involved in artisanal mining and the surrounding
communities, as well as reducing the impact of artisanal mining on the environment.

Conclusions

A majority of participant in this study had limited awareness and knowledge about
the health risks associated with Hg and As exposures, irrespective of economic activities
or educational level. However, there was significant variability among the various
groups. Overall, miners were more knowledgeable than individuals in other occupations,
and men had a higher degree of awareness than women. In fact, a majority of miners
identified Hg as a health hazard. The impact of As exposure was less known by the
participants. At a minimum, based on the findings of this study, it is recommended
that a health promotion campaign be established in Rwamagasa Village, Tanzania that
addresses the health hazards associated with Hg and As. The overall lack of knowledge,
combined with minimal environmental monitoring and controlled waste management practices,
highlights the need for health education, surveillance, and policy changes. Future
research that examines the pathways of contamination, exposure, and the burden of
disease is also needed.

Competing interests

The authors declare that they have no competing interests. It should be noted that
Twigg Gold is not engaged or associated with artisanal mining in the Rwamagasa belt
or anywhere else.

Authors’ contributions

EC designed the study, developed the survey, supervised the data collection, analyzed
the data and wrote the paper. DSKT contributed to the study design and development
of the survey, the interpretation of the findings, as well as the drafting and writing
of the manuscript. DD contributed to the development of the overall study design and
interpretation of results. MD contributed to the study design and survey. SEN contributed
to the study design, survey, and analysis/interpretation of the data. EK contributed
to the study design and data analysis. All authors read and approved the final manuscript.

Acknowledgements

The authors acknowledge the Catholic University of Health and Allied Sciences, the
University of Colorado Denver, and the University of Calgary for the collaboration
of resources that made this possible. Special thanks go to Twigg Gold Limited who
contributed funding to support this project. The authors would also like to thank
all the participants in this study.

References

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meeting on social and labour issues in small-scale mining (TMSSM). Geneva: International Labour Office; 1999.